Temperature Estimation in Inverter-Fed Machines Using High-Frequency Carrier Signal Injection

Temperature monitoring using the injection of a high-frequency carrier signal voltage is proposed in this paper. The carrier signal voltage is used to estimate the transient impedance of the system, which is a function of the stator transient resistance and, therefore, the windingspsila temperature. The variation of the stator transient impedancepsilas phase angle is used to track the temperature of the stator windings. The method can be implemented in standard inverter-fed drives with no additional hardware, with minimal computational requirements, and with practically no interference with the regular operation of the drive.